This invention relates to a mechanism and method for supporting a circuit card within a housing.
Various standard forms of circuit cards are known, for example, circuit cards in accordance with the PCI (Peripheral Component Interconnect) standards. Such cards are provided with electrical and mechanical mountings along first and second edges, which means that there is a free corner of the card which is typically unsupported. This can lead to problems in environments where vibration is possible.
In some applications, extremely strict standards are set with regard to the ability to withstand vibration of a unit comprising such a card. For example, in the telecommunications environment, there are extremely rigorous requirements with regard to ensuring that components can operate reliably when subject to vibration due to normal office and/or seismic causes.
There is a need, therefore, to define a structure that can minimise the vulnerability of a card to vibration. One difficulty in addressing this with respect to the mounting of, for example, a card such as a PCI card, is that the length of the card may not be defined by the appropriate standards, for example by the PCI standard specification. As a result, individual cards may have different lengths.
An aim of the invention is to provide a mechanism and method of supporting a part of a circuit card, for example the free corner of a PCI card, which can address the problem of minimizing vibration, while taking account of the fact that different cards to be supported may be of different lengths.
Particular and preferred aspects of the invention are set out in the accompanying independent and dependent claims. Combinations of features from the dependent claims may be combined with features of the independent claims as appropriate and not merely as explicitly set out in the claims.
In accordance with one aspect of the invention, there is provided a support mechanism for a circuit card. The support mechanism includes a support member that defines a guide. A card engaging member has a guide follower that slideably engages the guide such that the card engaging member is slideable with respect to the support member to a position at which it engages the circuit card.
An embodiment of the present invention thus enables the supporting of a part of the circuit card, for example a free corner, through the card engaging member (slider) and the support member (slide), which co-operate to support the card. The provision of the sliding inter-engagement of the slider and the slide means that the slider be slid along the guide on the slide to a position appropriate for supporting a card of any one of a number of lengths. This facilitates the initial installation of a card, as one support mechanism can support many different card lengths. Accordingly, it is not necessary to hold a set of different supports for different cards. Also, it facilitates the replacement of the circuit card, as the slider can simply be adjusted to a position appropriate for another card of another length.
An advantageous arrangement is for one of the guide and the guide follower to be configured as a rail and the other of the guide and guide follower to be configured as a slot having a complementary shape to the rail. The rail can project from the member on which it is formed so that the slot formed on the other member simply engages over the projecting rail.
The slider can be arranged to be held in a slideable engagement with respect to the slide simply by means of the inter-engagement of the slot and the rail, without any other securing arrangements. For example, the rail can have a head portion that is wider than a base portion. One example of this provides a rail with a dovetail-shaped cross-section.
The guide on the slide may be in the form of a rail, with the guide follower on the slider having the slot of co-operating shape. Alternatively, the guide follower on the slider may be in the form of a rail, with the guide follower on the slide having the slot of co-operating shape.
The slider may have first and second projections forming a jaw for receiving the circuit card. The first and second projections can thus define a slot therebetween for receiving the circuit card. The slider can include a projection, for example within the slot, for engaging in a hole in the circuit card.
In a preferred embodiment of the invention, the slide includes a wall portion for dividing a card receiving bay from a further bay within a housing. The slide can also include formations for securing the slide within the housing. These can take the form of, for example, a flange and/or a threaded hole for receiving a screw. The slide and/or the slider can be formed of an insulating plastics material.
In accordance with another aspect of the invention, there is provided electrical apparatus including a housing, a circuit card and a support mechanism for supporting a part of the circuit card within the housing. The support mechanism includes a support member (slide) defining a guide and a card engaging member (slider) having a guide follower that slideably engages the guide such that the slider is slideable with respect to the support member to a position to engage the part (e.g. a free corner) of the circuit card.
The electrical apparatus can further include a processor card carrying a processor. The slide can be configured to form a dividing wall between a circuit card bay for receiving the circuit card and a processor card bay for receiving the processor card. The slide can thus serve to separate respective flows of cooling air over the circuit card and the processor card from respective fan units. This enable minimisation of the airflow needed for the respective cards (typically a processor card will require more cooling than other cards) and with this a minimisation of the noise generated and optimisation of power consumption for the electrical apparatus as a whole. The apparatus could, for example, be a computer including a processor and a further circuit card (e.g. a PCI card).
In accordance with a further aspect of the invention, there is provided a method of supporting part of a circuit card (e.g., a free corner of a PCI card) within a housing, the method comprising locating a support guide within the housing and sliding a card engaging member (slider) having a guide follower along the guide to a position at which the card engaging member engages the part of the card.
An embodiment of the invention is thus able to accommodate and support a circuit card of any one of a range of lengths in a flexible manner that facilitates initial installation and subsequent replacement of such cards.